/*

 * Copyright (c) 2017, 2018, Red Hat, Inc. All rights reserved.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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/**

 * @test TestMemoryMXBeans

 * @key gc

 * @requires vm.gc.Epsilon

 * @summary Test JMX memory beans

 * @modules java.base/jdk.internal.misc

 *          java.management

 * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC          -Xmx1g TestMemoryMXBeans   -1 1024

 * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -Xms1g   -Xmx1g TestMemoryMXBeans 1024 1024

 * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -Xms128m -Xmx1g TestMemoryMXBeans  128 1024

 */

import java.lang.management.*;

import java.util.*;

public class TestMemoryMXBeans {

    static volatile Object sink;

    public static void main(String[] args) throws Exception {

        if (args.length < 2) {

            throw new IllegalStateException("Should provide expected heap sizes");

        }

        long initSize = 1L * Integer.parseInt(args[0]) * 1024 * 1024;

        long maxSize =  1L * Integer.parseInt(args[1]) * 1024 * 1024;

        testMemoryBean(initSize, maxSize);

        testAllocs();

    }

    public static void testMemoryBean(long initSize, long maxSize) {

        MemoryMXBean memoryMXBean = ManagementFactory.getMemoryMXBean();

        long heapInit = memoryMXBean.getHeapMemoryUsage().getInit();

        long heapMax = memoryMXBean.getHeapMemoryUsage().getMax();

        long nonHeapInit = memoryMXBean.getNonHeapMemoryUsage().getInit();

        long nonHeapMax = memoryMXBean.getNonHeapMemoryUsage().getMax();

        if (initSize > 0 && heapInit != initSize) {

            throw new IllegalStateException("Init heap size is wrong: " + heapInit + " vs " + initSize);

        }

        if (maxSize > 0 && heapMax != maxSize) {

            throw new IllegalStateException("Max heap size is wrong: " + heapMax + " vs " + maxSize);

        }

    }

    public static void testAllocs() {

        MemoryMXBean memoryMXBean = ManagementFactory.getMemoryMXBean();

        // Do lazy inits first:

        long heapUsed1 = memoryMXBean.getHeapMemoryUsage().getUsed();

        sink = new int[1024*1024];

        long heapUsed2 = memoryMXBean.getHeapMemoryUsage().getUsed();

        // Compute how much we waste during the calls themselves:

        heapUsed1 = memoryMXBean.getHeapMemoryUsage().getUsed();

        heapUsed2 = memoryMXBean.getHeapMemoryUsage().getUsed();

        long adj = heapUsed2 - heapUsed1;

        heapUsed1 = memoryMXBean.getHeapMemoryUsage().getUsed();

        sink = new int[1024*1024];

        heapUsed2 = memoryMXBean.getHeapMemoryUsage().getUsed();

        long diff = heapUsed2 - heapUsed1 - adj;

        long min = 8 + 4*1024*1024;

        long max = 16 + 4*1024*1024;

        if (!(min <= diff && diff <= max)) {

           throw new IllegalStateException("Allocation did not change used space right: " + diff + " should be in [" + min + ", " + max + "]");

        }

    }

}